
/* Copyright 1998 by the Massachusetts Institute of Technology.
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting
 * documentation, and that the name of M.I.T. not be used in
 * advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is"
 * without express or implied warranty.
 */

#include "ares_setup.h"

#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_NAMESER_H
#include <arpa/nameser.h>
#else
#include "nameser.h"
#endif

#include "ares.h"
#include "ares_private.h" /* for the memdebug */

/* Simply decodes a length-encoded character string. The first byte of the
 * input is the length of the string to be returned and the bytes thereafter
 * are the characters of the string. The returned result will be NULL
 * terminated.
 */
int ares_expand_string(const unsigned char* encoded,
    const unsigned char* abuf,
    int alen,
    unsigned char** s,
    long* enclen)
{
    unsigned char* q;
    union {
        ssize_t sig;
        size_t uns;
    } elen;

    if (encoded == abuf + alen)
        return ARES_EBADSTR;

    elen.uns = *encoded;
    if (encoded + elen.sig + 1 > abuf + alen)
        return ARES_EBADSTR;

    encoded++;

    *s = ares_malloc(elen.uns + 1);
    if (*s == NULL)
        return ARES_ENOMEM;
    q = *s;
    strncpy((char*)q, (char*)encoded, elen.uns);
    q[elen.uns] = '\0';

    *s = q;

    *enclen = (long)(elen.sig + 1);

    return ARES_SUCCESS;
}
